The present invention relates to a method of manufacturing a plasma addressed electro-optical display having a flat panel structure in which a display cell is superimposed on a plasma cell, and particularly to a method of manufacturing discharge electrodes and barrier ribs formed on the plasma cell.
A plasma addressed electro-optical display making use of a plasma cell for addressing a display cell has been known, for example, from Japanese Patent Laid-open No. Hei 4-265931. As shown in FIG. 7, this plasma addressed electro-optical display has a flat panel structure including a display cell 1, a plasma cell 2, and a common intermediate substrate 3 interposed therebetween. The plasma cell 2 includes a lower substrate 8 joined to the intermediate substrate 3 with a gap kept therebetween, in which gap an ionizable gas is sealed. Discharge electrodes 9 are formed on the inner surface of the lower substrate 8 in a pattern of stripes. The discharge electrodes 9 are printed and baked on the flat lower substrate 8 by a screen printing process or the like. Barrier ribs 10 are formed in such a manner that each barrier rib 10 partitions two adjacent pairs of the discharge electrodes 9 from each other, to thereby divide the gap in which the ionizable gas is sealed into discharge channels 12. The barrier ribs 10 are also printed and baked by the screen printing process or the like such that tops thereof are in contact with the lower surface of the intermediate substrate 3. A pair of discharge electrodes 9 contained in each discharge channel 12 function as an anode A and a cathode K to generate plasma discharge therebetween. The structure shown in FIG. 7, in which the anodes A and the cathodes K are formed on the same plane, is called "a planar discharge structure". In addition, the intermediate substrate 3 is joined to the lower substrate 8 with glass frit 11 or the like.
Meanwhile, the display cell 1 includes a transparent upper substrate 4. The upper substrate 4 is stuck on the intermediate substrate 3 using a sealant 6 or the like with a specific gas kept therebetween. The gap is filled with an electro-optical material such as liquid crystal 7. Signal electrodes 5 are formed on the inner surface of the upper substrate 4 in such a manner as to be perpendicular to the striped discharge channels 12. A matrix of pixels are defined at points at which the signal electrodes 5 cross the discharge channels 12.
In the plasma addressed electro-optical display having such a configuration, display drive is performed by switchingly scanning rows of the discharge channels 12 in which plasma discharge is to be performed in linear sequence and applying image signals to columns of the signal electrodes 5 on the display cell 1 side in synchronization with the scanning. The generation of plasma discharge in each discharge channel 12 between the anode A and cathode K having the flat electrode structure causes the interior of the discharge channel 12 to be uniformly at an anode potential, thus effecting pixel selection for each row. In other words, the discharge channel 12 functions as a sampling switch. Then, by applying an image signal to each pixel in a state in which such a plasma sampling switch is conductive, the sampling is performed to control turn-on/off of the pixel. After the plasma sampling switch is turned into a non-conductive state, the image signal thus sampled is held in the pixel as it is.
In the case where the above planar discharge structure is employed for a transmission type plasma addressed electro-optical display, there arises a disadvantage in which the opening ratio of the pixels is sacrificed because the light shielding discharge electrodes 9 are provided in the discharge channels 12. To cope with such a disadvantage, there has been proposed a plasma addressed electro-optical display, shown in FIG. 8, having a side surface discharge structure (also called a facing discharge structure or a wall discharge structure). In FIG. 8, for an easy understanding, parts corresponding to those of the plasma addressed electro-optical display of the planar discharge structure shown in FIG. 7 are indicated by the corresponding reference numerals. In the side surface discharge structure, a discharge channel 12 includes a pair of discharge electrodes 9 having side surfaces facing to each other and barrier ribs 10 each being matched onto the upper surface of the discharge electrode 9. The side surfaces, facing to each other, of the pair of the discharge electrodes 9 exposed in the discharge channel 12 function as an anode A and a cathode K to generate plasma discharge therebetween. Differently from the planar discharge structure, the side surface discharge structure ensures a high opening ratio because the anodes A and the cathodes K are not present on the bottom surfaces of the discharge channels 12, causing an advantage in terms of luminance.
FIG. 9 is a typical perspective view showing a method of manufacturing discharge electrodes 9 and barrier ribs 10 in the side surface discharge structure. In the related art method, the discharge electrodes 9 were formed by printing a conductive material (conductive paste) in a pattern of stripes by screen printing, and the barrier ribs 10 were formed by printing an insulating material (insulating paste) on the pattern of the discharge electrodes 9 using the same screen mask. In this method, however, since the discharge electrodes 9 or the barrier ribs 10 must be formed high to some degree, it is necessary to repeat screen printing for ensuring the thickness of the discharge electrodes 9 or the barrier ribs 10. For example, the barrier ribs 10 are formed by repeating about 10 times the screen printing. This makes the working time longer and may cause failure due to adhesion of dust. In this method, accurate positioning is also required for matching the barrier ribs 10 onto the discharge electrodes 9, which takes a lot of labor. To facilitate the positioning therebetween, the barrier ribs 10 must be laminated and printed on the discharge electrodes 9 using the same screen mask. In this case, after printing the conductive paste for forming the discharge electrodes 9, the conductive paste is required to be dried. Then, the screen mask is cleaned, and the insulating paste (a glass paste), which is exchanged from the conductive paste, is printed for forming the barrier ribs 10. The above related art manufacturing method, therefore, necessarily adopts batch processing, thereby causing a problem in mass-production.